Tree Vegetable Interaction in Vegetable Agroforestry Systems

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• Tree Vegetable Interaction in Vegetable
  Agroforestry Systems
• Progress Report
• Agustin R. Mercado, Jr
• ICRAF
• .

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TMPEGS

• Technology
• Develop economically viable and
  ecologically-sound vegetable-agroforestry (VAF)
  systems

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Overall hypothesis
In intensive vegetable production system in the
uplands, monoculture systems are not sustainable,
but integrating trees is feasible and offers
better prospects.
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Vegetable Agroforestry System (VAF) Research
goal

• Tree-vegetable integration on farm with minimal
  negative interaction, thus increasing
  productivity, economic profitability, nutrient
  use efficiency and environmental services

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VAF Research Issues

• AF systems
• Segregate
• Integrate
• Boundary planting
• Parklands
• Alleycropping or hedgerow intercropping
• Tree species
• Timber trees
• Fruit trees
• Canopy type broad, medium, narrow
• Vegetable types
• Crucifers Cabbages, Broccoli, Squash
• Tubers Potato,
• Solanaceous Tomato, eggplant,

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Specific hypotheses

• Vegetable based agroforestry (VAF) systems
  provide better productivity, increase fertilizer
  use efficiency (FUE), increase profitability and
  improve environmental services than vegetable
  monoculture system
• Application of model allows a more rapid
  progress in on-farm trials and site-management
  designs
• Integration (domestication) of indigenous tree
  vegetables offers additional option for sustained
  supply of vegetables for poor rural households.

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• Two research topics
• VAF tree-soil-crop interaction
• Domestication of indigenous tree vegetables

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General objectives

• To understand the nature of vegetable-soil-tree
  interactions in different types of tree
  integration on vegetable systems as the
  determinant for agro-silvocultural management
  options for enhancing the productivity of all
  components ( tree, vegetable, etc).
• To examine service functions provided by VAF
  systems such as nutrient safety-net and nutrient
  pump functions, carbon stocks (above-and
  belowground) and build up of soil organic matter
  (SOM)

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Specific objectives

• To determine existing VAF systems and understand
  its potential and constraints
• To evaluate existing VAF systems on light capture
  and tree growth and spatial vegetable
  productivity in relation to tree distance.
• To improve VAF systems by understanding
  vegetable soil tree interaction and employing
  appropriate agro-silvocultural practices in order
  to attain optimum productivity of all components.
• To test the hypothesis that tree roots act as
  safety-net for leached nutrients in intensive
  vegetable production system
• To collect and evaluate indigenous tree
  vegetables under farmers management

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Ongoing and planned research activities

• Vegetable farming system diagnosis (VFSD)
• Assessment of existing vegetable based
  agroforestry systems.
• VAF system improvement.
• Optimum light transmission as basis for
  silvicultural management (spacing, thinning,
  pruning, etc).
• Vegetable and tree growth and productivity.
• Tree-vegetable matching

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• Testing the hypothesis that tree roots act as
  safety-nets. Increased fertilizer use efficiency
  and reduction of fertilizer leaching
  (particularly on nitrate) thus avoiding
  contamination to water sources. (If 15N enriched
  fertilizer is available).
• Testing the hypothesis that trees act as nutrient
  pump. Use of depth placement of 15N method. (If
  15N isotope enriched fertilizer is available).
• Quantification of environmental services (C
  sequestration contribution of trees to soil
  organic matter build up (use of 13C method) and
  aboveground C stocks. Develop tree growth and
  allometric models)

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Deliverables

• Recommendation for vegetable- tree combination
  and management with minimal negative interaction
• Improved options for tree spacing and
  vegetable-tree intercrop patterns
• Profitable vegetable-tree systems identified

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Net benefit T (2y2-2y1)-D
D
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D
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Activities conducted so far

• Assessment of existing VAF systems covering 21
  farms, 2 AF systems, 6 tree species, 8
  vegetables, 4 aspects. Data collected were tree
  parameters (stem diameter, tree height, canopy
  height and width), spatial performance of
  vegetables (height, stem diameter, crown width,
  biomass), spatial light transmission (fish eye
  photography/quantum light meter)
• Focus group discussion with 15 VAF farmers on
  various ways of integrating trees on vegetable
  farms and their practices and experiences on tree
  and vegetable managements addressing
  tree-vegetable competition and complementarity.
• Nursery establishment and management of
  indigenous tree vegetables and medicinal trees.
  ,

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Eucalyptus robusta tomato at Gunayans farm at
Bul-ogan, Sungco, Lantapan.
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Eucalyptus- tomato interaction under boundary
planting system
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Three zones of tree-crop interaction in vegetable
agroforestry systems
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• Effect was due to
• Light competition (aboveground)
• Nutrient competition

Effects were due to Aboveround (light
competition) Belowground (water, nutrients, etc)
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Proportion of total light transmitted spatially
using fish-eye photography analyzed with gap
light analyzer software. Farmer removed
approximately 40 of the canopy
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Net complementarity as a simple tool in assessing
appropriate tree-vegetable integration

• Net complementarity degree of
  complementarity-degree of competitiveness
• Degree of complementarity relative yield (at
  complementarity zone) 1 x distance of influence
• Degree of competitiveness 1- relative yield (at
  competition zone) x distance of influence
• Relative yield at complementarity zone yield at
  complementarity zone/neutral zone
• Relative yield at competition zone yield at
  competition zone/neutral zone

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Three zones of tree-vegetable interaction in
vegetable agroforestry systems
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Influence of timber tree species on net
complementarity
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Influence of vegetable crops on net
complementarity
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Influence of aspects on net complementarity
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Domestication of indigenous tree vegetables

• Objectives
• - Collect and propagate indigenous tree
  vegetables
• - Household food and nutritional security
  (available 365 days a year)
• - Environment friendly (no pesticides, better
  carbon sequestration)
• - Seed banking (in situ)
• - Reduced production risks
• Indigenous tree vegetable species
• Gnetum gnemon Bago
• Abelmuchos manihot Lagikway
• Sesbania sesban Katuray
• Moringa oliefera Malunggay
• Looking for more entries
• Evaluation activities
• - Propagation methods (clonal propagation and
  nursery establishment at Claveria)
• - As contour hedgerows
• - As live fences

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• Medicinal trees
• Cinnamomum mindanensi (Kalingag)
• Cinchona pubescens (Kenina)
• Camella sinensis (Tea)
• Cinnamomum verum (Cinnamon)
• Vitex negundo (Lagundi)
• Evaluation activities
• - Clonal propagation methods
• - As hedgerows (farmers managed) as SPA
• - As live fence (farmers managed) as SPA
• Progress so far
• Clonal chamber has been established
• Potted seedlings of 1000 pcs for each of the
  species have been raised
• Collection of more entries

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Summary and initial findings

• 1. Integration of trees on farm is only feasible
  if
• Complementarity is greater than competition (Net
  complementarity is 0). Net complementarity can
  be a simple tool for assessing appropriate
  tree-vegetable integration.
• The cumulative value of tree products is greater
  than the cumulative values of yield loss and crop
  displacement area (cropped area loss).
• 2. Optimum tree spacing or tree line (hedge
  spacing) in AF system can be achieved when two
  complementarity zones meet. Approximately 25-30
  meters apart.
• 3. Eucalyptus robusta, Eucalyptus torillana and
  Acacia mangium are promising trees for VAF system
• 4. Cabbage, Chinese cabbage, cualiflower and bell
  pepper are suitable vegetables for VAF

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Thank you very much indeed for listening!!